1. Field of the Invention:
This invention relates to a suspension for an automobile and, more particularly, to a suspension provided with a suspension arm connected pivotably to a car body at two connections spaced longitudinally of the car body from each other and supporting pivotably an axle carrier at two connections spaced from both said connections laterally of the car body.
2. Description of the Prior Art:
There has been proposed a suspension which is provided with a suspension arm connected pivotably to a car body through bushings at two front and rear connections and supporting pivotably an axle carrier at two front and rear connections, said suspension arm being generally L-shaped as viewed in plan (Japanese Patent Publication No. 38762/79). In this suspension are determined the positions of respective connections to meet such requirements that a straight line interconnecting the rear connection at the car body side and the rear connection at the axle carrier side is orthogonal to a center line of a wheel on a grounding surface and a straight line interconnecting the front and rear connections at the car body side is crossed at a predetermined angle to a center line of the car body, and so on.
In said suspension, when the spring constants of bushings disposed respectively at the front and rear connections at the car body side of the suspension arm are set to be soft to increase a longitudinal compliance, toe-out tendency of the wheel is increased when backward force such as braking force is applied to the wheel.
Also, when lateral force is applied to the wheel, the rear connection at the car body side of the suspension arm is offset rearward from a center of the axle carrier, so that the wheel has somewhat toe-in tendency. On the other hand, since the rear connection at the car body side of the suspension arm is restricted in its disposition, the degree of freedom of selecting toe characteristics of the wheel is few.
An independent suspension for a rear wheel described in Japanese Utility Model Public Disclosure (KOKAI) No. 192805/82 has one of bifurcated portions provided on a trailing arm and formed to be less deformable vertically and deformable laterally. Thus, problems similar to those of said suspension are encountered in that while controllability can be improved, displacements of the wheel in longitudinal and lateral directions are affected by the hardness of the bushings respectively disposed in the bifurcated portions and the hardness of bushings disposed on the car body side of a rod connected respectively with the trailing arm and the car body to regulate lateral movement of the trailing arm.
An independent suspension for a rear wheel described in Japanese Utility Model Public Disclosure No. 52107/85 includes a first rigid lateral link, a second rigid link disposed forwardly of the first lateral link and a member disposed slantwise and spanned between the first and second links, the member being connected on an outward end thereof to the first link and on an inward end to the second link and being formed such that it has sufficient elasticity longitudinally of a car body and high rigidity upwardly and downwardly.
According to the suspension, the connection between the inward end of the member and the second link is moved inwardly by deformation of the member when a backward force acts on a wheel suspended by the suspension. Thus, the toe-in tendency of the wheel can be obtained. However, the amount of the toe-in obtained is small because the inward movement of the connection is restricted. Further, there occurs substantially no toe-in, when a lateral force acts on the wheel, because the member resists deformation laterally.